Tracer mechanism



May 7, 1963 N. M. MATusEwlcz `3,088,857

TRACER MECHANISM Filed Nov. ,26, 1958 INVENTOR. NICHOLAS M. MATUSEWICZATTOR N EYS United States Patent Y Oh ice 3,038,857 TRACER MECHANESMNicholas M. Matusewicz, Upland, Calit., assigner to the United States ofAmerica as represented by the Secretary of the Navy Filed Nov. 26, 1958,Ser. No. 776,655

1 Claim. (Ci. 149-33) (Granted under Title 3S, US. Code (1952), sec.266) The invention described herein may be manufactured and used by orfor the Goverment of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

This invention relates to a tracer mechanism for use as a target, moreparticularly, it relates to tracer mechanisms incorporating improvedtracer compositions.

The tracer head of this invention is for use as a photoactive source tobe attached to rockets and bombs to permit photographing of theirtrajectories.

A satisfactory tracer head to permit adequate photography for weapon andvehicle evaluation must furnish a trajectory-continuous airbornephotoactive source. Additionally, the dare composition used should beone which furnishes maximum continuous luminosity for the weight of thematerial, as Vspace limitations are obviously critical.

Tracers used in .the past have been subject to a number ofdisadvantages. Previous tracers were of the instantaneous llash type`and furnished no time-Wise continuity of visibility from point oflaunch to a desired point of the trajectory of the missile. This is inpart due to the fact that previous pyrotechnic formulations used in thetracers contained a fuel-oxidizer system designed to provide oxygen inamounts barely below the point of detonation so that supposedly acomposition would be formed providing maximum oxidation withoutdetonation. Theoretical and experimental yanalysis of these compositionshave shown that most `of the available oxygen for combustion was notbeing utilized for this purpose. A further disadvantage of prior artpyrotechnic compositions used in tracers is the fact that they providedlow photoactivity to volume ratio due to their chemical composition andthe fact that they could not be effectively consolidated. The space in arocket head which is available for the pyrotechnic composition is quitelimited. This accentuates the necessity for a pyrotechnic compositionwhich can be eifectively consolidated and which will produce highluminosity for a relatively extended time.

It is therefore an object `of this invention to provide a tracer headwhich furnishes la trajectory-continuous, airborne photoactive sourcewhich can be photographed for weapon and vehicle evaluation purposes.

It is another object of this invention to provide a pyrotechniccomposition for a tracer head which can be readily consolidated andwhich provides maximum luminosity over an extended time per Weight andvolume of the composition.

It is a further object of `this invention to provide a pyrotechniccomposition for tracer heads in which lsubstantially all of Itheavailable oxygen from the oxidizer is utilized for combustion of thefuel present.

It has been found that the above and other objects can be accomplishedby the combination of a tracer head of suitable construction; separateignition means for a pyrotechnic composition; and a pyrotechniccomposition comprising 4an oxidizing agent from the class consisting ofnitrates and perchlorates of alkali metals and ammonium, and a fuelcomprising a material from the class consisting of magnesium, aluminum,boron and mixtures thereof to which composition has been added asemicatalytic constituent from the class consisting of man- 3,f88,857Patented May 7, 1963 ganese dioxide, tungstic acid, molybdic acid,cerium nitrate, thorium nitrate, uranium nitrate, ammonium metavanadate,cerium oxalate, magnesium hydroxide, sodium metaperiodate, magnesiumtrisilicate, mercurio cyanide, barium peroxide, lithium nitrate, bariumnitrate, sodium cobaltinitrite, sodium iluoride, sodium bismuthate,cerrous ammonium nitrate, selenium metal, columbium metal, tantalummetal, and aluminum-calcium alloy.

The invention is best understood by reference to the followingdescription taken in connection with the accompanying drawing which is ahorizontal cross-section of the tracer head and tiring mechanism for thepyrotechnic composition.

Referring to the drawing, the tracer head is represented generally -bythe numeral 10 and the consolidated -pyrotechnic composition is shown at11. The tracer head 10 is provided with flame exit ports 12 so arrangedand constructed that flames from the burning pyrotechnic will be emittedin a direction perpendicular to the direction of travel of the tracerhead. A coating 13 of firstiire or igniter mixture is painted on the endof .the consolidated pyrotechnic composition 11 for ignition of thecomposition. A spiral 14 of fibrous material impregnated with anignition mixture containing essentially gunpowder is coated with thefirst lire mixture and sealed to the coating 13. For igniting the firsttire mixture a conventional type acceleration arming fuze 15 is providedhaving a spring loaded tiring pin which res a primer which in turnactuates a detonator located in the.

rotor 18 of the fuze. It will be noted that the forward end of the fuzecase is cone-shaped and is so placed with respect to the exit ports 12as to cause flames to be exited out of the ports. The firing pin, primerand detonator, being conventional, are not shown in detail. The fuze isof the type Idisclosed in the copending application of Winitred F. Sappentitled Rocket Fuze and led in the U.S. Patent Office March 12, 1953,under Serial No. 342,039, now U.S. Patent No. 2,948,219. The fuze 15 ismounted in the aft end of the head by means of sleeve 20 and set Screw21. The aft end of the head is provided with threads as shown forattaching the head to a conventional rocket motor used to propel theliare head. The tracer head -operates `as follows: Upon launch of therocket or bomb carrying the head, the fuze is armed by acceleration ofthe missile. Arming of the fuze mechanism releases the tiring pin tofire the primer which, in turn, ignites the detonator, the detonatorserving as a relay charge to tire the igniter composition and iirstfire. The iirst fire upon ignition burns at a temperature sufficientlyhigh to ignite lthe pyrotechnic composition. The burning of thepyrotechnic mixture creates flames and hot gases which because of theirconnernent create high pressures. This pressure causes iiame-s to beforced out of the exit ports 12. The pyro technic 'burns for a period oftime determined by the amount of pyrotechnic, mesh `size of theconstituents, consolidation pressures and variations in the formulation.The method and construction for igniting the pyro technic composition isnot critical but is merely one that has been found to be operative.Other methods may be used. It will be noted that the cone-shaped end ofthe fuze body 15 provides a bale adjacent the exi-t ports l2 for .theburning gas and flames from the end-burning pyrotechnic. The cone-shapedend forms a diffuser cone to direct the gases and flames out of the exitports. The construction and arrangement of the ports and diffuser coneso that the gases and iiames are vented at a direction perpendicular tothe line of ight and axis of the tracer is an important feature of theinvention.

To this composition sutlicient N-butyl acetate was added to make thepaste pourable and to permit the iirst iire to be painted onto thepyrotechnic in a thin layer.

Various pyrotechnic compositions were made up and tested. 'Ihe basiccomposition is that of Example I. The additional examples 'are ofcompositions made by adding the ingredients shown to Example I. A11parts are by weight.

EXAMPLE I The composition consisted of 60 parts of `atomized magnesium(-100 to +200 mesh), 4G parts of sodium nitrate (200 mesh) and 5 partsof Laminac 4116 added as ya binder. This compound gave a candlepower of400,000.

EXAMQPLE II Additive to Example I Candlepower 2% parts MnOz (-20D mesh)430, 000

EXAMPLE III 2% parts of Cerium Oxalate (100 mesh) 435, 000

EXAMPLE IV 2% parts of Antimony Potassium Tartrate 100 mesh) 340, 000

EXAMPLE V 2% parts o! lead peroxide (-100 mesh) 360, 000

EXAMPLE VI 2% parts of ferrie oxide 200 mesh) 440, 000

EXAIWPLE VII 2% parts potassium permanganate 390, 000

EXAMPLE VIII 2%ttirltltiflfffffflif. 350, 000

EXAMPLE IX znpfzias o1 thorium dioxide and 2% parts of manganese 400,000

EXAMPLE X 2% parts o! tungsten trioxide 425, 000

EXAMPLE XI of tungsten trioxide and 2% parts of manganesev 415 000EXAMPLE XII 2% parts of molybdenum trioxide 450, 000

EXAMPLE XIII 2leirogdmolybdenum trioxide and 2% parts manga- 450 0U()EXAMPLE XIV 2% parts cerium oxide 455, 000

EXAM P LE XV 2% parts of cerium oxide and 2% parts manganese 455, 000

The composition range of Example I is as follows:

Wt. percent Sodium nitrate 35-45 Magnesium 54-64 Laminac 4116 1-2Compositions were made and tested in which sodium nitrate of the abovecomposition was replaced by each of the following oxidizing agents:potassium nitrate, ammonium nitrate, ammonium perchlorate and potassiumTo all of the above compositions the following semicatalytic modifyingagents were added within the range of 1 to 10 percent by weight andtested; the additives were added to obtain controlled effects in thecatalytic action on burning of the tracer compositions: manganesedioxide, tungstie acid, molybdic acid, ceriurn nitrate, thorium nitrate,uranium nitrate, ammonium nitrate, ammonium metavanadate, cen'umoxalate, magnesium hydroxide, sodium metaperiodate, magnesiumtrisilicate, mercurio cyanide, barium peroxide, lithium nitrate, bariumnitrate, sodium cobaltinitrite, sodium uoride, sodium bismuthate, cerousammonium nitrate, selenium metal, columbiurn metal, tantalum metal,aluminumcalcium alloy. All of the compositions produced a continuousburning flare with good luminosity. The incorporation of thesemi-catalytic constituent in the pyrotechnic increases the amount ofoxygen liberated during burning, thereby permitting more completecombustion of metal fuels and thus producing a higher luminosity perunit volume. The Laminac 4116 in the above compositions may be replacedby a nitrocellulose binder with equally good resul-ts. Other binderswhich may be used in equal amounts are fiuorocarbon waxes, such as,Kel-F waxes. The amount of ybinder used is somewhat critical as too muchproduces too much carbon which takes a prohibitive amount of oxygen fromthe oxidizer thus resulting in the production of smoke only.

Laminac 4116 is an unsaturated polyester dissolved in a reactivemonomer. The monomer is styrene. 'Ihe polyester is of relatively lowmolecular weight and is manufactured from one of the group ofunsaturated dibasic acids, such as maleic and pumeric acid, and from oneof the group of saturated dibasic acids, such as phthalic, isophthalic,and adipic acid; and from one or more from a group of polyols, such asethylene glycol, propylene glycol, and dipropylene glycol. The polyestersolution is a liquid with a specilic gravity of 1.10, a viscosity of 4poises and an acid number of from 10 to 30.

The pyroteehnic mixture is prepared 'as follows: the dry ingredients areblended for thirty minutes in a Lancaster counter-current rapid batchmixer. The binder is then added and blending is continued for one hour.The blended mixture is then screened through a 20 mesh screen, placed inshallow trays and oven cured at F. for 72 hours. The cured mixture isrescreened through a 20 mesh screen and is then ready to be loaded intothe pyrotechnic case 10. The pyrotechnic composition is loaded asfollows: 'with the pyrotechnic case l0 placed in a fixture to preventpermanent deformation of the case under consolidation loads, thepyrotechnic formulation is pressed into the case in two increments ofape proximately 150 grams each, using 100,000 p.s.i. on each increment.y

An ignition mixture, not shown, may be coated on the end of theconsolidated pyrotechnic -and the rst tire mixture 13 applied to it. Thecomposition of the ignition mixture may -fbe as follows: 50 percent -byWeight of a mixture consisting of 90 percent by weight of bariumchromate (-325 mesh) and percent by weight of 'boron (-325 mesh), and 50percent by weight of a mixture bf 50 parts by weight of the pyrotechnicmix ture and 5 parts by weight of Laminac 4116.

Obviously many modifications and variations of the present invention arepossible in .the light of the above teachings. I-t is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced lotherwise than as specifically described.

What is claimed is:

A pyrotechnic composition screened through a 20 mesh screen consistingessentially of to 45 percent sodium nitrate; from 54 to 64 percentmagnesium; and from 1 to 2 percent nitrocellulose binder.

References Cited in the le of this patent UNITED STATES PATENTS 594,594Bostwick Nov. 30, 1897 613,021 Schwartz Oct. 25, 1898 1,025,500 Wieseret a1. May 7, 1912 2,035,509 Schladt Mar. 31, 1936 2,149,314 SchladtMar. 7, 1939 2,410,801 Audrieth Nov. 12, 1946 2,700,603 Hart et al. Jan.25, 1955 2,829,596 Loedding Apr. 8, 1958 2,868,129 Johnson et al Jan.13, 1959 2,968,542 Brock Ian. 17, 1961 OTHER REFERENCES MilitaryExplosives, TM9-1910 TO11A134, April 1955, pp. 276, 287, and 294.

